1. Field of the Invention
The present invention relates to a computer wireless peripheral device. More particularly, the present invention relates to a bi-directional communication wireless peripheral device and a power saving method thereof.
2. Description of Related Art
With the rapid development of information technology, computers have become an indispensable tool in daily life. A conventional computer architecture includes a computer host, a display, and several peripheral equipments connected to the computer host. Along with the quick development of this industry, in addition, competition and the demand for light, thin, short and small exterior features result from the enhancement of operation speed and user-friendly interface for all users. Therefore, people related to the field of peripheral equipment have developed some wireless peripheral devices having wireless I/O characteristics, e.g., wireless mice and wireless keyboards, etc, which are mainly directed to improving the convenience for operators and avoiding the trouble of a clutter of wires.
However, as the above wireless peripheral devices generally use batteries as their main electrical power supplying source, so the power consumption must be highly considered for the wireless peripheral device. A power management strategy is usually set in the common wireless peripheral device by means of software or hardware. If the power management strategy of the wireless peripheral device is unsatisfactory, users should change or charge batteries for this device frequently, thus causing inconvenience to users.
FIG. 1 is a state diagram of a wireless peripheral device managed by a conventional power management strategy. Referring to FIG. 1, there are three operational modes, namely a working mode 101, a stand-by mode 102, and a power off mode 103. A conventional wireless peripheral device usually enters the working mode 101 firstly after the activation is completed, and at this time, the power consumption is maximal. During a preset time T1, if the wireless peripheral device does not receive a user operation, the conventional wireless peripheral device will enter the stand-by mode 102 from the working mode 101. Generally speaking, in the stand-by mode 102, usually certain specific functions of the wireless peripheral device are turned off, and certain necessary functions remain working. For example, as for a wireless optical mouse when in the stand-by mode 102, a light-emitting diode (LED) of an optical sensor under the optical mouse may flash or become dim, the operating clock frequency of its micro-processor may become lower from time to time, or the optical sensor is completely turned off to reduce power consumption, and only a key-pushed function is reserved to wake up the optical mouse to reinstate the working mode 101.
If the wireless peripheral device does not receive a user operation during the stand-by mode for another preset time T2, it then enters the power off mode 103 from the stand-by mode 102. Generally speaking, the power off mode 103 refers to the device consuming almost no power in this mode. The user cannot make the wireless peripheral device enter the working mode 101 from the power off mode 103 unless a standard power-on procedure is performed. However, the preset times T1 and T2 are not particularly defined, and can be defined by the behavior pattern of consumers to this product. If the time T1 or T2 is defined too short, the user may feel that the operation of the wireless peripheral device is not sensitive. If the time T1 or T2 is defined too long, large power is consumed.